The invention relates to electroluminescent lamp devices, and more particularly, to electroluminescent lamp devices attached to tires of vehicles.
Electroluminescent lamps are known in various forms, including flat panels and wires, and have been proposed for a variety of products, including watches, instrument panels, vehicle body moldings, brake light displays, and athletic shoes.
For example, U.S. Pat. No. 6,037,865 to Heinz et al. discloses an electroluminescent band incorporated in molding attached to the outer surface of a vehicle body and U.S. Pat. No. 5,611,621 discloses electroluminescent lamps attached to a basketball shoe.
The invention relates to a use of electroluminescent (EL) lamps on tires, which may be ornamental or decorative, or may be used to improve visibility of the vehicle. An EL lamp in accordance with the invention may be a thin sheet or panel EL lamp made in the form of a logo or trademark, or a decorative shape, on the tire sidewall. Also, a wire EL lamp could be attached in a decorative or ornamental way. A wire EL lamp could also be shaped to spell a trademark. Other EL lamp devices could be used in similar ways.
According to the invention, an EL device for a tire includes an EL lamp, a power supply, a control device, and means for mounting or interfacing the EL device to a tire.
According to a preferred embodiment, the EL device includes a rubber patch to retain the EL lamp and power storage device. The patch may have a recess in which the EL lamp is mounted. The control electronics may be cured into a portion of the patch. An adhesive strip is provided on the side of the patch opposite from the recess for securing the patch to the sidewall of a tire.
A thin battery and the control electronics may be attached to the EL lamp to form a package, that may be readily mounted directly to a tire sidewall or installed in a patch as described above. For convenience, the package may be removable to allow for recharging of the battery and later remounting. In addition, the package may be removable and replaceable to allow change of EL lamp designs.
According to another aspect of the invention, the means for mounting the EL lamp to a tire may include a layer of a material for mechanically and chemically isolating the EL device from the stresses in the tire. A layer of foamed elastomeric material provides a suitable isolating material. The isolating material may have on one face an adhesive compatible with tire rubber mix and on an opposite face an adhesive compatible with a backing substrate (for example, the rubber patch) for the EL lamp. The isolating material advantageously isolates the EL lamp from some of the stresses the tire experiences in flexing during rolling. In addition, the isolating material acts as a barrier to oils and other compounds that may migrate out of the tire sidewall. A foamed elastomer is particularly useful for an EL lamp of the thin sheet form.
The portion of the tire on which the EL lamp or device package is mounted may be provided with a recess corresponding in shape to the patch or EL device package. The walls of the recess may be configured to contain or support the electronics.
According to another embodiment, the means for mounting the EL lamp to a tire relates to a wire EL lamp, and includes a narrow groove cut or formed in the tire to capture and retain the wire EL lamp. The wire may be held by an adhesive applied in the groove. Alternatively, the groove is formed in a c-shape with edges that overlap the open recess area of the groove to capture and retain the wire. Of course, adhesive could be also added to the c-shaped groove to assist in retaining the wire. The accompanying power storage device and control electronics may conveniently be integrated in a rubber patch, which may be attached to the tire.
The device according to the invention may be powered by a battery as the power storage device. According to one embodiment, the battery is of the type formed as a flat cell or cells, and is mounted between the EL lamp and the tire sidewall. For a wire EL lamp, the battery may be mounted to the tire in a suitable location and connected to the wire in an appropriate manner.
Alternatively, a power generating device such as is described in U.S. patent application Ser. No. 10/143,535, filed May 10, 2002, and assigned to the owner of the present invention, may be used. Such a device includes a piezoelectric fiber matrix that generates electric charge from mechanical strain.
A power generating device may include a rechargeable battery, a storage capacitor, or may work directly with the EL lamp.
According to one embodiment, the piezoelectric fiber matrix is mounted between the EL lamp and the tire sidewall, for example, in a rubber patch as described above. According to another embodiment, the piezoelectric fiber matrix is mounted separately to the tire sidewall and connected to the wire EL lamp.
A power generating device as described above is mounted to the tire at a location where it will experience strain during rotation of the tire. Possible locations include the tire sidewall and the crown. A rubber patch or EL assembly as described above are mounted to the tire sidewall where flexing occurs in the ground contacting portion of the tire.
According to another alternative, the power supply is mounted in the interior cavity of the tire, and the invention includes means for connecting the power supply to the EL lamp on the outer surface of the tire.
According to yet another alternative, the power generating device is an electromagnetic generator having wire coils mounted to the wheel rim and a magnet mounted to a stationary part of the vehicle.